1. Field of the Invention
The present invention relates to an active control sound generator. More particularly, the present invention relates to an active control sound generator that controls tone in accordance with the RPM of an engine and load conditions of a vehicle.
2. Description of Related Art
In general, as noise generated when a vehicle travels, there are various noises such as engine noise, friction noise due to rolling friction in traveling, flow noise due to air flow.
In order to solve such a problem, it is possible to prevent deterioration of comport for passengers in vehicles by mounting an expensive soundproofing material in the vehicles.
However, since most noises of vehicles are flow noise and noise such as booming sound at a specific bandwidth due to pulsation generated by an engine etc., it is very difficult to completely block the noises in the vehicles.
A resonator was mounted in vehicles in the related art to remove the booming noise due to pulsation, but the resonator has an effect only on removal of noise at a specific frequency band, such that there is a limit in removing well the noise generated at the intake system of a vehicle engine.
In contrast, sound intentionally generated at a predetermined frequency band can improve comfort for drivers.
For example, a specific bike includes components and is controlled to generate sound improving riding comfort of a rider by making exhaust sound so that sound at a specific frequency band is output.
Further, for a vehicle too, when a vehicle travels in a sport mode, that is, an operation mode for providing traveling feel like in traveling of a sports vehicle, a technology of controlling the suspension, the shifting way, and output sound is used.
However, the technology of the related art has a problem in that the entire noise level increases, when a sporty tone increases, and the maximum of the sporty tone is limited by the entire noise level.
Further, a common sound generator, which can perform ON/OFF control as position control of a motor, has a problem in that linear tone change is impossible because the position change of a valve to the noise feature change in ON/OFF control is fast.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.